See below...
David Boyes <[EMAIL PROTECTED]> wrote:
>
> > My question is if it is easy, difficult or impossible to port
> > large existing
> > S/390 applications written in assembler to run under LINUX on a 390 or
> > z/series platform? I am not talking about a batch
> > application but about a
> > server type application that currently uses S/390 facilities
> > and operating
> > system services such as TCP/IP Socket APIs, multi-tasking and
> > Data Spaces.
>
> This will be quite difficult. Most of the APIs either don't exist or are
> quite different, multitasking will need to be restructured, and Linux
> doesn't know anything about data spaces. You'll effectively need to
> restructure most of the critical sections of the application (if not the
> whole application), and at that point, you're better off switching to a
> higher-level language such as C and starting over, taking advantage of the
> Linux APIs.
If you're considering possibilities - let me suggest working through
a rewrite of your application with Systems/C. Systems/C will allow
a function-by-function rewrite (Systems/C can use your own assembler
entry/exit macros, etc...) Then, you have a nice migration path
to move an existing application to C.
When that is done, and the application operates exactly the same
(on OS/390) as it did before. You'll have a much better chance of
moving it to Linux/390.
Also - Systems/C (and Systems/C++) are the first commercial C/C++
compilers for Linux/390. In some tests, Systems/C generated code
that ran 20% faster than the gnu compiler's code.
>
> > Have other S/390 software vendors ported assembler products of this
> > complexity or is the effort so large as to not be feasible?.
>
> See above. Unix applications are pretty easy; this stuff won't be.
A very true statement!
- Dave Rivers -
--
[EMAIL PROTECTED] Work: (919) 676-0847
Get your mainframe programming tools at http://www.dignus.com
